Chronic obstructive pulmonary diseases (COPD), which includes such entities as cystic fibrosis, chronic bronchitis, and emphysema, are steadily increasing in frequency, possibly due to continued smoking, increasing air pollution, and the continued aging of the population. COPD is characterized by edema of the mucous membranes, which line the interior walls of the tracheobronchial tree. When the mucosa accumulates an abnormal quantity of liquid, the profuse and thickened serous fluid excreted may seriously affect ventilation in the alveoli. The mucus resists movement up the walls of the tracheobronchial tree, normally efficiently accomplished by the cilia throughout the airways which are also destroyed. Consequently, the serous fluid can form mucus plugs, which can shut off alveoli or entire airways. In addition to secretion accumulation, airway obstruction can occur because the tubes collapse due to destruction of connective tissue. This reduces the ability to get oxygen into the blood and carbon dioxide out of the blood.
Asthma is the most common form of bronchoconstrictive disease and pathologically involves constriction of the bronchioles, hypertrophy of the muscles of the bronchioles, and a characteristic infiltrate of eosinophils. Both asthma and COPD, are characterized by the constriction or collapse of airway passages in the lungs that are not supported by cartilage. This condition is marked by labored breathing accompanied by wheezing, by a sense of constriction in the chest, and often by attacks of coughing and gasping. Individuals who are afflicted may attempt to compensate by blowing harder only to have the airways collapse further. A person with poor resulting ventilation suffers from a number of metabolic conditions including accumulation of carbon dioxide. These individuals also often have hyperinflated enlarged lungs and barrel-shaped chests.
A wide variety of drugs are available for treating the symptoms of COPD but none is curative. Cystic fibrosis, chronic bronchitis, and emphysema are typically treated with agents to thin and dry up the secretions and with antibiotics to combat infection and with bronchodilators. These drugs include potassium iodide, antihistamines, various antibiotics, beta agonists and aminophylline. Unfortunately, a large number of patients are not responsive to these medications or become non-responsive after prolonged periods of treatment. For severe cases involving collapsed air passages, surgeons have endeavored to alleviate this disabling condition by either removing a portion of the lungs or constricting the volume of lung available for respiration by stapling off sections thereof. The result is that functionally the diaphragm and muscles in the chest wall operate on a smaller lung volume which may improve air movement for some individuals. These operations are quite risky and are associated with a large number of deaths. Patients undergoing these treatments are quite ill and these procedures are considered final options.
Notwithstanding the conventional treatments available, there exists a need in the art for an effective treatment for chronic obstructive pulmonary diseases, such as cystic fibrosis, chronic bronchitis, emphysema and asthma. Specifically, there is a need for effective treatment for individuals with obstructed airway passages to restore pulmonary function which only requires minimal surgery.